Chlorination of polymeric materials



Patented June 27, 194i CHLORINATION OF POLYM ERIC v ,MATERIALS a William'Jolm' Roy Evans, Blacklcy, England, as-

'signorto'lmperial Chemical IndustriesLimited, acorporation of Great Britain Y 1 1 in, Drawing. Application June'e'f, ia ns'eriar No. 400,099. In Great Britain July 1, 1940 i I 5 Claims. This invention relates to the manufacture of polymeric materials and moreparti'cularlytol an improved process for the production of chlorin ated polyvinyl chloride.

j 1't,has already been proposed in Il3ritish speei flcation No...401,2 '0.' to. chlorinate polyvinyl chloride by the action -of chlorineon suspensions of such polymers in carbon tetrachloride or on their solutions in tetrachloroethane. When highly polymerised vinyl chloride is'to be chlorinated further according to themethods of the above proposal difiiculties are experienced in isolating the chlorinatedmaterial, orjin obtaining a product which is sufliciently highly. chlorinated ,for

some purposes or which shows the required solubility inorganic solvents. For instanc'efwhen highly polymerised vinyl chloride dissolved in tetrachloroethane is acted upon with chlorine, unless very large proportions of the solvent are employed, not only are difiiculties experienced in agitating the solution and in passing chlorine into the same but when the product is isolated by adding the reaction medium to a coagulant a gelatinous mass of material is obtained unless ineonveniently low temperatures are used during precipitation. The gelatinous mass cannot easily be freed from solvent. Further when suspensions of polyvinyl chloride in carbon tetrachloride are used, although difficulties in isolating the chlorinated product are not experienced, it has not been found possible to obtain products with a sufliciently high chlorine content or with suflicient solubility in organic solvents to be usefulfor making films or other shapes.

We have now found that, contrary to expectation, these difiiculties are avoided by chlorinating polyvinyl chloride suspended in a mixture of carbon tetrachloride and tetrachloroethane.

According to the present invention therefore, highly polymerised vinyl chloride is chlorinated further by a process which comprises interacting chlorine with polyvinyl chloride in the presence of a mixture of carbon tetrachloride and tetrachloroethane.

The polyvinyl chloride to be used for the purposes of this invention may be obtained in any known manner, for example, b polymerising an aqueous emulsion of vinyl chloride by the methods described in British specification No. 410,132.

The proportions of the polymer to the mixture of the organic liquids, namely, the carbon tetrachloride and the tetrachloroethane, are not critical but may conveniently vary between 1 part of the polymer to 14 to 17 parts of the mixture.

of the tetrachlorloethane in the mixture" likewise are not critical, but may conveniently vary between 0.5. to 1.25, partsof carbon tetrachloride to heart of tetrachloroethane. v I The further chlorinated material may be recovered as hereinafter described or' maybe used directly for example as, aningredient of coating compositions." In carrying the ,process "ofgthe presentinvention into, efiect the highly polymer- .ised .vinyl' chloride is agitated at an elevated ter'npferature, for example at 'a temperature at v.or nearthe boiling point of. the particular mixture of the organic liquidsbeing used while chlorine is passed into the agitated suspension. If

presence ,of'light or actinic'radiation inforder to increase the rate of chlorination. When the required degreej oi chlorination has been attained, the liquid so-obtained may be used directly as already mentioned or the polymer may be recovered by slowly adding to the liquid, a coagulant such as a lower alcohol, for example methanol or ethanol. cipitated are obtained as finely divided, while solids which may be recovered by filtration, and are useful, especially in the form of solutions in organic liquids, for the production of films and the like.

The following example illustrates but doesnot to limit the invention, all parts being by weight.

' Example tively, was agitated, heated to and maintained at v a temperature of 95-98" C. and illuminated with a 500 watt electric lamp, whilst chlorine was passed in at the rate of parts per hour for 5 hours. Hydrogen chloride was evolved and a clear solution obtained. The solution was cooled to C. and 800 parts of industrial ethyl alcohol were added over a period of '15 minutes, with stirring. The chlorinated polymer separated from the solution as a finely divided powder.

which was removed from the liquid by filtering,

boiled with 400 parts of ethyl alcohol for 10 minutes, filtered again and dried in a vacuum oven at a temperature of 50-60 C. for 8 hours. The finely divided white powder so obtained had a chlorine content of 63.1 per cent and a2 per cent solution in tetrachloroethanc had a relative viscosity of 14.2, as measured in a No. 2 Ostwald viscometer at 20 C.

desired the reaction may becarried out in the,

The chlorinated polymers when pre- For purposes oi comparison the process of the above example was repeated using 1,900 parts of 7 solubility in organic liquids such as ethyl acetate, butyl acetate and xylene. Byreason of this i insolubility the powder was not suitable forthe production of films.

For further comparative purposes theprocess, of the example was repeated using 3,200 parts of tetrachioroethane instead oi the mixture organic liquids. At first a stiil gel wa iormed' which caused diillculty in stirring andin passing in chlorine, although after about 1 hours the reaction medium became mobile. On coagulating with ethanol as described above the polymer was obtained as a gelatinous mass from which it was diflicult to remov the solvent. Iti'was, however, found that this chlorinated polymer couldbe iso- 'lated as a coarse white powder with 'a chlorin'e content of 64.1 per centand satisfactorysolu- .bility and film-forming properties according to the method described lnBritish specification 'No.

485,115, but this m'ethod involved the employment of large quantities of the coagulating liq-' uid,,took a considerable time to operate and reunited the use of convenientlyilow temperatures.

.1 claim:

fliLProcess for the manufacture of chlorinated polyvinyl chloride which comprises reacting chlorine with a suspension of polyvinylrchloride l in a mixture of from 0.5 to 1. 25 parts by weight of carbon tetrachloride and one part by weight w of tetraohloroethane in which the proportion 01 the polymer to the mixture oi organic liquids lies in the range of 1 partby weight oI-the polyvinyl chloride to 14 to 17 parts by weight of the mixed liquids so as to produce a chlorinated product soluble in ethyl acetate, butyl acetate and xylene. 2. Processior the manufacture of chlorinated polyvinyl chloride whichcompris'es. reacting chlorine with. a suspension of polyvinyl chloride in .10 a mixture of from 0.5 to 1.25 parts by weight of carbon tetrachloride and 1 part by weight of -tetrachloroethane so as to produce a chlorinated xylene. V l5 3-..Process for the manufacture of chlorinated polyvinyl'chloride which comprises reacting chlorine with a suspension of piyvinyl chloride in a mixture ofirom" 0.5 to 1.25 parts by weight of "carbon tetrachloride and one part by weight of .Otetrachloroethane at a temperature not removed by more than C. from the boiling tempera-- v ture of the mixed liquids so as to produce a chicrinated product solublein ethyl acetate, b utyl acetate-and xylenei v a :3 4. Process for the manuia'ctureof chlorinated [ployvinyl chloride which comprisesreacting chlorine with a suspension of polyvinyl chloride in a mixture of from 0.5 to 1.25 parts by weight of .carbon tetrachloride and one part by weight of tetrachloroethane and recovering solidchiorinated polyvinyl chloride from the resulting solution so as o produce a chlorinated product soluble in' ethyl acetate, butyl acetateand xylene;

5. Process according to claim 4 in which the solid chlorinated polyvinyl chloride is recovered from thesolution by coagulation with a lower aliphatic 'alcohol, at a temperature not higher t n fc 1 a W JOHN ROYEVANS.

' product soluble in ethyl acetate, butyl acetate and 

